Normal nerve and muscle depend upon intact innervation to provide regulatory or "trophic" effect. It has been shown that any measure which blocks the flow of motor impulses and deprives the effector organ of excitatory input for a period of time can cause "disuse supersensitivity" in that organ, as well as in associated spinal reflexes. Supersensitive nerves and innervated structures react abnormally to stimuli according to Cannon and Rosenbleuth's law of denervation:

"When a unit is destroyed, in a series of efferent neurons, an increased irritability to chemical agents develops in the isolated structure of structures, the effect being maximal in the part directly denervated."

That means, when a nerve is functioning below par and is not functioning properly (neuropathy), it becomes supersensitive and behaves erratically. This principle is fundamental and universal, yet is not well-known or credited. Peripheral neuropathy parallels the aging process, most intense at the weight-bearing and mobility areas of the body.

The Supersensitivity Of Denervated Structures: A Law Of DenervationExperimental Biology Monographs